Driving mechanism



M. J. WIGHTMAN 1,925,127

TLM o S\ y l o Oo OLO i O l ubi O S0) Yu /v/ mill/@ 1mg/mgm rNvr-:NTOR

ATTORNEY Sep. 5, 1933. M, wlGHTMAN 1,925,127

DRIVING MECHANISM Original Filed May lO, 1924 4 Sheets-Sheet 2 www,

I lNvENToR i BY t UM ATTORNEY Sept. 5, 1933. M, Jl W|GHTMAN 1,925,127

DRIVING MECHANISM original Filed May l0, 1924 4 Sheets-Sheet 5 ggd.

, mkl. w,

VEN OR ATTORNEY Sept. 5, 1933. M. J. WIGHTMAN DRIVING MECHANI SM Original Filed May 10, 1924 4 Sheets-Sheet 4 INVE TOR ATTORNEY Patented Sept. 5, 1933 DRIVING MECHANISM Merle J. Wightman, Seattle, Wash., assigner to Domestic Stoker Company, New York, N. Y., a corporation of Delaware Original application May 10, 1924', Serial No.

Divided and this application January 25, 1929. Serial No. 334,906

6 Claims. (Cl. 'i4-53) This invention relates generally to -mechanical fuel stokers and more particularly to a combined stoking device and burner especially adapted for use with solid fuel in furnaces of the type use in heating residences or in other relatively small installations.

I have described and claimed a device of this type in my Patent No. 1,703,130, granted February 26, 1929, of which the present application is a l division. The device therein and hereafter described comprises an apparatus which will automatically feed and burn solid fuel with a minimum degree of attention and in such a manner as to provide a substantially complete or perfect l' combustion thereof and an efficient application and use of the heat thus obtained.

The apparatus includes in combination a fire pot positioned within a furnace or other heating device, a fuel supply bin or hopper exterior of -0 said furnace or spaced from said fire pot, a helical screw conveyor adapted to convey fuel from the hopper to the fire pot, and means for operating said conveyor. 1

In the preferred embodiment of my invention, as heretofore described in' said patent, means are also provided for supplying air to said fire pot to support combustion therein and means are likewise provided for transporting ashes away from the re pot.

The various previously described parts are actuated by a motor operating through suitable gearing. Means are provided for controlling the speed of combustion by retarding or advancing the rate of fuel and air supply, these two features being capable of independent regulation.

The present application pertains particularly to improvements in stolzer mechanism and to` that feature of my invention relating to a drive mechanism for a fuel conveyor shaft.

In the drawings,`

Figure 1 is a view in end elevation (with an unimportant part broken away) of a fuel handling apparatus embodying `the invention.

Figure 2 is a view inside elevation on a reduced scale of the apparatus shown in Figure 1.

Figure 3 is a plan view of the apparatus shown in Figure 2 taken on the line 3 3.

Figure 4 is a vertical section on an enlarged scale taken approximately on the line 4-4 of Figure 1.

Figure 5 is a sectional view taken on the line 5 5 of Figure 4.

Figure 6 is a horizontal section of the device shown in Figure 4.

Figure '7 is a front elevation on an enlarged scale of the clutch driving device shown in Figure 1.

Referring to the drawings for a more detailed description of the invention, the general organisation of structure includes a burner connected 60 through the concentrically disposed tubular members 2l and 22 with a fuel hopper 23v and the outlet pipe 24 of an air blower 25. The inner tubular member 21 is fitted with a screw conveyor 26 for feeding fuel from the hopper 23 into 65 the base portion ofthe burner or fire pot 20. In order to operate the fuel feeding device andthe lower electric motor 27 is directly coupled to the blower and is indirectly connected to the shaft of the fuel feeding conveyor 26 through a 70 reducing gear set 28 and an intermittently acting clutch device 29. The air blast from the blower 25 passes through outlet pipe 24 and enters the annular space between tubular members 20A and 21. This air blast is supplied to the burning fuel 7b in fire pot 2i) by means of suitable ports connecting said re pot with saidv annular space.

Another element of the general organization of structure residesin an ash-removing device which includes aA screw conveyor 30 mounted beneath 80 the draft conduit 22 and extending into the base of the furnace beneath the fire pot 20 as is shown in Figure 2 ofthe drawings.V At a point beneath the hopper 23 the ash conveyor turns olf' at right angles and inclines upwardly to deliver ashes into a suitable receptacle 31 as indicated in Figure 1. A sprocket wheel 32 on the end of the ash conveyor shaft is connected through a sprocket chain 33 with a driving sprocket wheel 34 on the shaft of the fuel conveyor 26 so that the ash conveyor is driven in exact accordance with the operation, of the fuel` feed conveyor.

The mechanism employed for feeding fuel from,4 the hopper 23 into the burner 20 is arrangedv to intermittently rotate the screw conveyor 26 95 through a predetermined fractionalV part of a revolutionwith each operating movement.A Referring to Figures 4 and 6 ofthe drawings it will be seen thatthe conveyor shaft 46 passes through the reduced base portion 76 of the hopper 23 and is journaled in a boss 77 formed on the forward face of the hopper base. The outer end of the conveyor shaft 46 is provided with driving clutch mechanism indicated generally at 29 and illustrated particularly in Figures Vl, 4, 6, and '7 ofthe drawings.

Referring to this-clutch mechanism, the sleeve 78, which is provided withv the flange 79, is keyed to the conveyor operating shaft 46. Thisfsleeve, as shown in Figure 5, has a sector shaped gap 80 in which is located the driving lug 81 which is secured to the drum 82. By means presently to be described the drum 82 is given an oscillatory movement in which it moves a greater distance on its forward stroke than upon its return. The difference 'between its two strokes, which may be adjusted as will be explained later, is what determines the extent to which the sleeve 78, and hence the conveyor operating shaft 46, will be advanced by the driving lug 8l at each complete oscillation of the clutch mechanism. Obviously, if the forward and return strokes of the lug 81 were equal, that lug would merely oscllate back and forth in the sector-shaped gap of the flange 79 without advancing the flange or the conveyor shaft 46 to which it is secured.

The means for oscillating the drum 82 as above stated will now be described. Surrounding the drum 82 is the split band 83 upon the two ends of which are secured the brackets 84 and 85. To the bracket 84 is pivoted one end of the clutch operating arm 86 which at its other end is pivoted to the connecting rod 87 operated by the motor driven crank 88. The arm 86 is also connected to the bracket 85 by means of the link 89. As a result of this construction, as the arm 86 is moved forwardly or in a counter-clockwise direction as viewed in Figure 7, it tightens the band 83 on the drum 82 and carries the band and drum. with it. So, also, the spring 90, which is interposed between the bracket 84 and the end of the rod 91, exerts suflicient force tending to move the arm toward the bracket 84 that even upon the return (clockwise) movement of the arm 86 the band 83 will grip the drum 82 with sufficient friction to carry the drum back with it, if the return movement of the drum is unobstructed.

In order that there may be the required difference between the forward and return strokes o1' movements of the drum 82 to effect the desired advance of the conveyor shaft, I provide means for obstructing the return movement of the drum 82 at any desired point on the return movement of the band 83 and arm 86. These means comprise the two segmental friction brake members 92, 93 located within the flange of the drum 82. The lever or regulating arm 94 is pivoted to the brake member 92, and has a projecting pin 95 adapted to contact with the other brake member 93. The spring 96 normally presses against the lever 94 in such a way as to tend to separate the adjacent edges of the two brake members and thus to expand them into frictional engagement with the inner surface of the ange of drum 82.

A fixed abutment 97 and an adjustable abutment 98 are provided for limiting the movement of the lever 94, which lever, as will now appear, operates to limit the rotary movement of the brake 92, 93 as a whole, as well as to control its frictional engagement with the drum 82.

Assume now that the parts are at the beginning of their forward stroke. The cushioned end 99 of lever 94 will then be in contact with the fixed abutment 97. The movement of the arm 86 in its counter-clockwise (forward) direction will, for reasons previously stated, carry with it the band 83 and drum 82, and also the brake members 92, 93 (which are pressed into frictional engagement with the drum 78 by the spring 96), and the brake controlling lever 94.

If, now, the adjustable abutment 98 were not so placed as to intercept the lever 94 in its forward movement, all of the parts above mentioned, including the drum 82 and its driving lug 81,

would oscillate back and forth together, the rel turn stroke of each being equal to its forward stroke. The result would be, as before stated, that the conveyor shaft would not be advanced at all. However, when the abutment 98 is placed in an intermediate position, as shown, for example in Figure 7, the end 99 of the lever 94 is arrested by it prior to the completion of the forward stroke of arm 86.

The result is that the brake also is arrested, its frictional engagement with drum 82 being lessened by the tendency of the lever 94 to move in a clockwise direction about its own pivot. The arm 86, band 83 and drum 82, however, continue on to the completion of the forward stroke. At the commencement of the return stroke the spring 96 again becomes effective to bring the brake members into frictional engagement with the drum 82, and, the brake being now free to rotate with the drum, all of the parts start to return together. However, before the end of the return stroke the end 99 of lever 94 is arrested by the xed abutment 97. This arrests the rotation of the brake members and, as will be obvious, at the same time increases the friction between the brake members and the drum 82 to a point where the friction between the brake and drum is greater than that between the drum and strap 83. Accordingly the drum is arrested also.

In subsequent operations of the clutch mechanism the same cycle is repeated. It is in this way that the return stroke of the drum is rendered ofrless extent than its forward stroke. Thus the distance between the abutments 97 and 98 measures the extent of the return stroke of the drum. The closer together these abutinents are placed the less will be the return stroke of the drum and the greater will be the difference between its forward and its return stroke. And as vabove suggested, the greater this difference the greater will be the advance of the conveyor operating shaft upon each operation of the clutch device.

Thus the maximum rate of feed is obtained when the adjustable abutment 98 is in its uppermostposition so that the lever 94 is not permitted any movement, and the minimum rate is determined by the location of a second fixed abutment 190. The adjustable abutment 98 may be placed anywhere between these two positions, depending upon the rate of feed desired. The position of the stop 98 may be fixed by a hand screw 101 which is utilized to lock the band 102 on which the stop 98 is carried in fixed angularposition. The band 102 is rotatably mounted on the boss 77 as is clearly shown in Figure 4 of the drawings.

The adjustable stop member 98 may, if desired, be left unlocked and free to be moved from a distance through a chain or other connection with a manual or thermostatic control device located in another part of the building in which the device is used.

The loose connection provided between the clutch drum 82 and the conveyor shaft through the gap in the fiange 79 affords an additional useful function and that is the capability of manually oscillating the conveyor shaft through a partial revolution for the purpose of dislodging clinkers or for any other purpose. To facilitate this a square recess 103 in the outer end of the conveyor shaft 46 provides for the introduction of the squared end of a crank or wrench for rocking the shaft. Should it be found desirable to increase the length of the normal operating stroke of the arm 86 the link 87 may be attached theretof at the'positon of the hole 109 insteadr of at the outer extremity of the arm.

In order to regulate the volume of the air supplied to the burner through the draft conduit 22 a butterfly or` damper valve 112 is provided in the air supply pipe 24 and a shaft 113 for adjusting the valve extends therefrom andv is journaled in a bracket lug 114 on the hopper base member 76.

Provision is made for automatically adjusting the position of the valve 112 to accord with the position of the feed control arm 98 and the rate at which fuel is fed to the burner. For this purpose a crank device 115 is adjustably carried by the shaft 113 and is engaged by a screw 115 passing through an arm 11'? xed to the shaft. Rotation of the screw 116 is utilized to vary the angular relation of the crank 115 to the valve shaft 113.

The automatic adjustment referred to is obtained by the cooperation of the crank 115 with a cam member 118 carried by the ring or band 102 which supports the feed control stop 98. It will be seen that the crank arm 115 is caused to engage and follow the contour of the cam 118 through the action of a Weight 119 conveniently forming the head of the adjusting screw 116. Further adjustment of the relation between the air valve 112 and the feed control mechanism to suit the requirements of different fuel may be obtained by varying the angular position of the cam 118 on its support. This is achieved by loosening the screw 118', adjusting the cam, and then locking the cam in adjusted position by turning the screw to its holding position. It will be seen that with the arrangement of adjusting mechanism shown any desired relation between the rate of feeding fuel and the rate of supply of air to the burner may be obtained and that the adjustment of the feed control arm 86 automatically produces a corresponding adjustment of the air valve 112.

The general operation as a complete operating unit of the described apparatus may be briey summed up as follows: The hopper 23 is lled with coal in a relatively finely divided grade such, for example, as the size known as buckwheat. A re having been kindled in the burner 20, current to the electric motor 27 is turned on and the blower 25 through its direct-coupled connection with the motor is started into operation. At the same time the crank 88 is set into rotation through the rotation of the worm wheel 104 in the reducing gear set 28 by the worm 105 directly driven from the motor shaft 106 through the flexible coupling 107, the crank 88 being mounted on the shaft 108 of the worm wheel 104.

The oscillation of the clutch operating arm through its operating connection with the crank 88, and the resulting intermittent operation of the fuel conveyor 26 has already been described. It will be clear that when once set into operation the fuel conveyor will continue to feed fuel to the burner, subject only to regulation of the rate of supply of fuel and air by variations in the position of the control arm, until the supply of fuel in the hopper khas been exhausted or until the supply of power to the motor has been shut off.

The driving connection between the fuel conveyor shaft and the ash removing device insures the automatic removal of ashes so that the apparatus operates with a minimum degree of attention, requiring only the replenishing of the hopper with a fresh supply of fuel every two or three 'days and the substitution of an empty ash receptacle for a filled one at relatively infrequent intervals.

1. A driving mechanism for a shaft to intermlttently rotate the same, comprising a clutch device carried by the vshaft and having an oscillatable operating arm, a clutch drum loosely coupled tothe shaft and having a clutch band on its external periphery, said operating arm being arranged to cause the band to grip the drum in the operating motion of the arm, an internal brake for the drum, a control arm connected to the internal brake, and means adapted to engage the control arm and operate the internal brake to lock the drum against rotation during a variable portion of the reverse movement of the operating arm and band.

2. A driving mechanism for a'shaft to intermittently rotate the same, comprising a continuously operable motor, a crank driven by the motor, a clutch device carried by the shaft and having an oscillatable operating arm actuated by the crank, a clutch drum loosely coupled to the shaft and having a clutch band on its external periphery, said operating arm being arranged to cause the band to grip the drum in the operating motion of the arm, an internal brake for the drum, a control arm connected to the internal brake, and means adapted to engage the control arm and operate the internal brake to lock the drum against rotation during a variable portion.

of the reverse movement of the operating arm and band.

3. An intermittent driving mechanism for a screw conveyor shaft comprising a continuously operable motor, a clutch drum on the conveyor shaft having a loosely coupled connection with the shaft, a clutch band carried on the external periphery of the drum, an oscillatable operating arm carried by the band, means connecting the oscillating arm to the motor to cause the band to grip the drum and rotate the same, expansion brake members mounted inside the drum, a control arm carried by one of the inside brake members and normally operating to cause the expan sion brake members to grip the drum, an adjustable stop member adapted to be engaged by the control arm in the operating movement of the clutch drum to loosen the expansion brake members a fixed stop adapted to be engaged by the control arm in the reverse movement of the parts, said control arm then acting to lock the expansion brake members against the drum and prevent further reverse rotation of the clutch drum with the band.

a. A driving mechanism for intermittently progressing a rotatable shaft,comprising a member loosely coupled to the shaft and adapted to actuate the shaft with a limited amount of lost motion, a reciprocating member frictionally connected to oscillate the loosely coupled member, a brake member frictionally connected to the loosely coupled member and means for regulating the relative frictional engagements of the reciprocating and brake members to arrest the loosely coupled member during a portion of its oscillation.

5. A driving mechanism for intermittently progressing a rotatable shaft, comprising a member loosely coupled to the shaft and adapted to actuate the shaft with a'limited amount of lost motion, a reciprocating member frictionally connected to oscillate the loosely coupled member, brake members frictionally connected to said tween the reciprocating lever and the feed worm shaft and adjustable means for overcoming the frictional resistance of the drive connection and arresting the said shaft relative to the said reciprocating lever during an adjustable portion of the movement of the reciprocating lever in one direction.

NIERLE J. WIGHTMAN. 

